In the scientific fields it is often necessary to manipulate fluid flow through conduits by opening, closing and diverting fluid flow to transport or mix various fluids from various sources. The most common example of this occurs in medicine where medicament (medication or fluid) infusing into a patient via an intravenous or central line) need to be mixed with another infusing medicament in a way that can be manipulated so as to allow or disallow the various infusions as required. These same fluid systems need to allow the practitioner direct sterile access so that a given medicine or fluid may be directly injected, pressure may be directly monitored, or body fluid may be directly removed for sampling.
A common way to accomplish this is through the use of medical stopcocks which are most commonly of the “3 way type” or less commonly “4 way type” (these stopcocks are shown in FIG. 1). These inventions allow ports to be opened or closed as need be to allow or disallow the flow of a given medicament or to allow direct access to the fluid system for the above stated reasons.
A common problem with the use of these 3 and 4 way medical stopcocks is the manipulation or setting of their flow patterns (operable or functional state) based on one's visual assessment. The user must rotate a central hub to align flow through the desired ports based on his or her ability to understand and interpret the functionality of the stopcock. This functionality is most commonly delineated by a single knob which points to the port that is closed, making interpretation of those that are open difficult. This lack of positive delineation leads to misinterpretation of flow patterns with concomitant errors in settings and associated medication errors which may lead to harm or death.
The difficulty in interpreting the flows that will be allowed from a given setting also limits the number of combinations (i.e. 4 way). This limit occurs because with stopcocks that offer more than four combinations (i.e. 4 way), interpretation and manipulation become too complicated and the chances for error increase exponentially. This limits the current technology and requires assembling two or more of the standard stopcocks in series (an arrangement known as a “manifold”) if more choices are required. This increases cost, complexity and each stopcock in the chain multiplies the chance of medication errors.
Relevant Prior Art:
3,957,082May 18, 1976Fuson4,566,480Jan. 28, 1986Parham5,144,972Sep. 8, 1992Dryden5,156,186Oct. 20, 1992Manska4,219,021Aug. 26, 1980Fink6,158,467Dec. 12, 2000Loo6,230,744May 15, 2001Ahrweiler6,418,966Jul. 6, 2002Loo6,457,488Oct. 1, 2002Loo6,953,450Oct. 11, 2005Baldwin7,232,428Jun. 19, 2007Inukai
All prior art stopcocks, including those listed above are fraught with less than adequate demarcations or indications for whether a given port is in the open or closed position. This problem yields difficulty and error in determining the functionality of the prior art stopcock at any given “setting.”
Manska's stopcock (5,156,186) does make an attempt to better delineate whether the given port is on or off, by having the “o” in “on” or “off” traverse between the two words, thereby spelling the status of the port it overlies as “on” or “off,” but also leaving remnants of words like “ff” over the other ports. This is an improvement over the prior art, but still requires reading, interpreting and assessing each port before the overall functional state can be determined. This modality does not let one interpret at a glance which ports are open and (in use) and is again associated with a greater degree of error than the present invention. This modality (Manska's) only allows up to a “3 way”complexity secondary to these limitations.
Loo's stopcocks (6,158,467, 6,418,966 and 6,457,488) do include a one sided central fluid path in the hub (on the knob side). This single sided central port only communicates with the outer ports, and does not allow for fluid flow all the way through the hub. Loo's stopcock functionality is very hard to interpret making it difficult to know which ports are open and which are closed. His designs include two separate non-mixing fluid paths which increases the complexity and chance for medication errors, particularly so with the lack of an adequate flow designation system. The optional central fluid flow path of the present invention offers a much needed advantage over this design and others, allowing fluid from an IV or other source to flow through the central hub, independent of the hubs rotated position with respect to the fluid conveyance ports (as is required by the Loo designs), thereby increasing overall functionality, useful ports, and ease in interpreting the functional state. The present invention, for instance, could allow fluid to continue flowing through the central port while all other ports were off (Loo's design has no means to accomplish this). Loo's designs only allow flow from the central port to the peripheral ports.